Small-sized microspectrometers in the existing art includes a plurality of optical components, such as a slit, a pair of waveguide sheets and a micrograting. After passing through the slit, light would travel within the gap formed between the pair of waveguide sheets and incident the micrograting, which then disperses the light into a plurality of spectral rays. The spectral rays incident a linear detector from the micrograting, and are converted into electrical signals by the linear detector. The electrical signals are analyzed by a processor or other external component to obtain the intensity of the spectral rays
Considering the limited size of microspectrometers, arrangement of the optical components of the microspectrometer has to be highly precise, and tolerance from assembly of the optical components has to be strictly controlled. Otherwise, stray lights would occur in the interior of the microspectrometer, leading to distorted measurements and reduced measurement accuracy of the microspectrometer.